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Crane hook scrapping standards and replacement cycles

2025-07-28 14:59:37

1. Scrapping standards (mandatory replacement conditions)

If any of the following defects occur in the hook, it must be immediately stopped and scrapped and may not be used again after repair:

Defect Type Specific judgment criteria Related regulatory basis
1. Crack - Any visible cracks (regardless of length or depth)
- Hidden cracks detected by magnetic particle testing (MT)		 ASME B30.10 / ISO 2415
2. Hook deformation - The hook opening exceeds 10% of the original size (e.g. original 50mm, now > 55mm) OSHA 1926.550 / EN 1677-1
3. Hook tip wear - Loss of cross-section ≥ 10% (measured by caliper) GB/T 10051.1
4. Thread damage - Thread slippage, deformation, and rust make the nut unable to tighten ISO 898-1 (bolt standard)
5. Severe rust - Rust depth ≥ 1mm or affects structural strength ASTM A668
6. Plastic deformation - Any part of the hook is irreversibly bent or twisted ISO 7597
7. Material Deterioration - High temperature operation leads to hardness reduction (＜HB 250) or metallographic structure changes (such as intergranular corrosion) ISO 4957 (Tool Steel Standard)

2. Replacement cycle (based on usage scenario)

The replacement of the hook depends not only on time, but also on the frequency of use, load conditions and environmental conditions :

Usage scenarios Recommended inspection/replacement cycle Key Focus
1. Conventional industry (such as workshop) -  Daily : Operator visual inspection
-  Yearly : Professional NDT inspection (MT/UT)
-  Replacement : 10 years or reach scrap standard		 Wear and deformation
2. High frequency use (such as ports) -Weekly  : Detailed inspection -Semi
-  annual : NDT inspection
-Replacement  : 5~7 years or reaching scrap standard		 Fatigue cracks, wear
3. Harsh environment (such as chemical industry, ocean) -Monthly  : Corrosion inspection -Quarterly  : NDT inspection -Replacement :  3~5 years or reaching scrap standard
 		 Rust, stress corrosion cracking
4. Personnel lifting (such as elevators) -  Daily inspection +  NDT every 3 months
-  Replacement : 5 years (mandatory) or reaching scrap standard		 Crack and anti-unhooking device reliability

3. Measures to prolong the life of the hook

  1. Correct use

    • Avoid overloading, oblique pulling and impact loads.

    • Use matching wire rope/sling (to prevent abnormal wear).

  2. Regular maintenance

    • Lubricate bearings/pins (once a month, use high temperature grease).

    • Clean the surface (especially in corrosive environments, apply anti-rust oil).

  3. Upgrade Materials

    • For high frequency or corrosive environment, alloy steel (such as 34CrMo4) or stainless steel hooks should be used .

4. Scrapping Process

  1. Identification and isolation : Hang a "Danger-Scrap" label and store separately.

  2. Destruction treatment : cutting or flattening to prevent misuse.

  3. Record archiving : Save the scrapping reason, date and test report (at least 3 years).

5. Comparison of International Standards

standard Scrap Standard Detection cycle
ASME B30.10 Crack, deformation 10%, wear 10% Annual NDT + Daily Inspection
ISO 2415 Cracks, deformation 15%, severe rust According to ISO 4309 cycle (usually half a year)
GB/T 10051 Cracks, deformation 10%, thread damage Monthly Inspection + Annual NDT

in conclusion

  1. The scrapping standards must be strictly enforced , and any fluke mentality may lead to accidents.

  2. The replacement cycle needs to be adjusted dynamically , and the cycle should be shortened in high-frequency, heavy-load or corrosive environments.

  3. Intelligent monitoring is the trend : it is recommended to introduce strain sensors or AI visual detection systems to monitor the hook status in real time.

Tip : For critical occasions (such as nuclear power and aerospace), it is recommended to increase the safety factor to ≥6 and adopt a double hook redundant design .

1. Scrapping standards (mandatory replacement conditions)

If any of the following defects occur in the hook, it must be immediately stopped and scrapped and may not be used again after repair:

Defect Type Specific judgment criteria Related regulatory basis
1. Crack - Any visible cracks (regardless of length or depth)
- Hidden cracks detected by magnetic particle testing (MT)		 ASME B30.10 / ISO 2415
2. Hook deformation - The hook opening exceeds 10% of the original size (e.g. original 50mm, now > 55mm) OSHA 1926.550 / EN 1677-1
3. Hook tip wear - Loss of cross-section ≥ 10% (measured by caliper) GB/T 10051.1
4. Thread damage - Thread slippage, deformation, and rust make the nut unable to tighten ISO 898-1 (bolt standard)
5. Severe rust - Rust depth ≥ 1mm or affects structural strength ASTM A668
6. Plastic deformation - Any part of the hook is irreversibly bent or twisted ISO 7597
7. Material Deterioration - High temperature operation leads to hardness reduction (＜HB 250) or metallographic structure changes (such as intergranular corrosion) ISO 4957 (Tool Steel Standard)

2. Replacement cycle (based on usage scenario)

The replacement of the hook depends not only on time, but also on the frequency of use, load conditions and environmental conditions :

Usage scenarios Recommended inspection/replacement cycle Key Focus
1. Conventional industry (such as workshop) -  Daily : Operator visual inspection
-  Yearly : Professional NDT inspection (MT/UT)
-  Replacement : 10 years or reach scrap standard		 Wear and deformation
2. High frequency use (such as ports) -Weekly  : Detailed inspection -Semi
-  annual : NDT inspection
-Replacement  : 5~7 years or reaching scrap standard		 Fatigue cracks, wear
3. Harsh environment (such as chemical industry, ocean) -Monthly  : Corrosion inspection -Quarterly  : NDT inspection -Replacement :  3~5 years or reaching scrap standard
 		 Rust, stress corrosion cracking
4. Personnel lifting (such as elevators) -  Daily inspection +  NDT every 3 months
-  Replacement : 5 years (mandatory) or reaching scrap standard		 Crack and anti-unhooking device reliability

3. Measures to prolong the life of the hook

  1. Correct use

    • Avoid overloading, oblique pulling and impact loads.

    • Use matching wire rope/sling (to prevent abnormal wear).

  2. Regular maintenance

    • Lubricate bearings/pins (once a month, use high temperature grease).

    • Clean the surface (especially in corrosive environments, apply anti-rust oil).

  3. Upgrade Materials

    • For high frequency or corrosive environment, alloy steel (such as 34CrMo4) or stainless steel hooks should be used .

4. Scrapping Process

  1. Identification and isolation : Hang a "Danger-Scrap" label and store separately.

  2. Destruction treatment : cutting or flattening to prevent misuse.

  3. Record archiving : Save the scrapping reason, date and test report (at least 3 years).

5. Comparison of International Standards

standard Scrap Standard Detection cycle
ASME B30.10 Crack, deformation 10%, wear 10% Annual NDT + Daily Inspection
ISO 2415 Cracks, deformation 15%, severe rust According to ISO 4309 cycle (usually half a year)
GB/T 10051 Cracks, deformation 10%, thread damage Monthly Inspection + Annual NDT

in conclusion

  1. The scrapping standards must be strictly enforced , and any fluke mentality may lead to accidents.

  2. The replacement cycle needs to be adjusted dynamically , and the cycle should be shortened in high-frequency, heavy-load or corrosive environments.

  3. Intelligent monitoring is the trend : it is recommended to introduce strain sensors or AI visual detection systems to monitor the hook status in real time.

Tip : For critical occasions (such as nuclear power and aerospace), it is recommended to increase the safety factor to ≥6 and adopt a double hook redundant design .

1. Scrapping standards (mandatory replacement conditions)

If any of the following defects occur in the hook, it must be immediately stopped and scrapped and may not be used again after repair:

Defect Type Specific judgment criteria Related regulatory basis
1. Crack - Any visible cracks (regardless of length or depth)
- Hidden cracks detected by magnetic particle testing (MT)		 ASME B30.10 / ISO 2415
2. Hook deformation - The hook opening exceeds 10% of the original size (e.g. original 50mm, now > 55mm) OSHA 1926.550 / EN 1677-1
3. Hook tip wear - Loss of cross-section ≥ 10% (measured by caliper) GB/T 10051.1
4. Thread damage - Thread slippage, deformation, and rust make the nut unable to tighten ISO 898-1 (bolt standard)
5. Severe rust - Rust depth ≥ 1mm or affects structural strength ASTM A668
6. Plastic deformation - Any part of the hook is irreversibly bent or twisted ISO 7597
7. Material Deterioration - High temperature operation leads to hardness reduction (＜HB 250) or metallographic structure changes (such as intergranular corrosion) ISO 4957 (Tool Steel Standard)

2. Replacement cycle (based on usage scenario)

The replacement of the hook depends not only on time, but also on the frequency of use, load conditions and environmental conditions :

Usage scenarios Recommended inspection/replacement cycle Key Focus
1. Conventional industry (such as workshop) -  Daily : Operator visual inspection
-  Yearly : Professional NDT inspection (MT/UT)
-  Replacement : 10 years or reach scrap standard		 Wear and deformation
2. High frequency use (such as ports) -Weekly  : Detailed inspection -Semi
-  annual : NDT inspection
-Replacement  : 5~7 years or reaching scrap standard		 Fatigue cracks, wear
3. Harsh environment (such as chemical industry, ocean) -Monthly  : Corrosion inspection -Quarterly  : NDT inspection -Replacement :  3~5 years or reaching scrap standard
 		 Rust, stress corrosion cracking
4. Personnel lifting (such as elevators) -  Daily inspection +  NDT every 3 months
-  Replacement : 5 years (mandatory) or reaching scrap standard		 Crack and anti-unhooking device reliability

3. Measures to prolong the life of the hook

  1. Correct use

    • Avoid overloading, oblique pulling and impact loads.

    • Use matching wire rope/sling (to prevent abnormal wear).

  2. Regular maintenance

    • Lubricate bearings/pins (once a month, use high temperature grease).

    • Clean the surface (especially in corrosive environments, apply anti-rust oil).

  3. Upgrade Materials

    • For high frequency or corrosive environment, alloy steel (such as 34CrMo4) or stainless steel hooks should be used .

4. Scrapping Process

  1. Identification and isolation : Hang a "Danger-Scrap" label and store separately.

  2. Destruction treatment : cutting or flattening to prevent misuse.

  3. Record archiving : Save the scrapping reason, date and test report (at least 3 years).

5. Comparison of International Standards

standard Scrap Standard Detection cycle
ASME B30.10 Crack, deformation 10%, wear 10% Annual NDT + Daily Inspection
ISO 2415 Cracks, deformation 15%, severe rust According to ISO 4309 cycle (usually half a year)
GB/T 10051 Cracks, deformation 10%, thread damage Monthly Inspection + Annual NDT

in conclusion

  1. The scrapping standards must be strictly enforced , and any fluke mentality may lead to accidents.

  2. The replacement cycle needs to be adjusted dynamically , and the cycle should be shortened in high-frequency, heavy-load or corrosive environments.

  3. Intelligent monitoring is the trend : it is recommended to introduce strain sensors or AI visual detection systems to monitor the hook status in real time.

Tip : For critical occasions (such as nuclear power and aerospace), it is recommended to increase the safety factor to ≥6 and adopt a double hook redundant design .

Pre: Safety Factor and Failure Analysis of Crane Hook
Next: Deformation correction method for crane hook

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